When we are evaluating a pet food or treat to sell at the store, there is an (ever-expanding) list of ingredients that we will not carry, and farmed salmon is definitely one of them. Some items we don’t like because the ingredients are harmful to the environment, some because practices are inhumane or these animals are fed things that might remain in the meat, and some because they are harmful to the animals that consume them. Farmed salmon has the special distinction as being all of these things.

Farming salmon is factory farming at its worst – it’s devastating to the environment, large overcrowded pens require massive amounts of antibiotics and pesticide usage to combat health problems, contagious diseases and escaped fish are a big risk to wild populations of fish, and the resulting product is high in PCBs and other chemicals.

The process of farming salmon encloses large numbers of fish in small pens, polluting the water with fecal matter and chemical waste. According to Scotland’s World Wildlife Fund, salmon farms there produce nitrogen wastes equal to a human population of more than nine million people.
Even industry insiders concede that a typical 200,000-fish salmon farm releases:
– nitrogen equal to 20,000 humans
– phosphorus equal to 25,000 humans, and
– fecal matter roughly equivalent to a city of 65,000 people.
(Hardy, 2000b).”–Goldburg, R. et al. (2001) Marine aquaculture in the United States: Environmental Impacts and Policy Options. Pew Ocean Commission, p.13).

Sea Lice, a dangerous parasite can be easily transferred to wild salmon as they swim by a salmon farm.

Overcrowded conditions lead to unhealthy conditions and outbreaks of contagious disease leading to massive antibiotic use – Fish farmers dose their fish to combat these outbreaks, (Chilean salmon farmers used nearly 850,000 pounds of antibiotics in 2007, according to http://na.oceana.org/) as well as large quantities of pesticides. These pesticides and dewormers also poison the water around them and kill important organisms on the ocean floor below. The result is a no-oxygen “dead zone” that can extend up to 500 feet. (–Goldburg, R. et al. (2001). Marine aquaculture in the United States: Environmental Impacts and Policy Options. Pew Ocean Commission, p. 13.)This excessive antibiotic use is also harmful to humans – “The use of antibiotics, however, is arguably a health risk for people and farmed fish, since it promotes the spread of antibiotic-resistance in both human and fish pathogens. At least a few types of bacteria associated with fish, such as Streptococcus, can be pathogenic to humans (Weinstein et al., 1997). If strains of these bacteria develop higher levels of resistance to antibiotics, infections by these bacteria may be difficult to treat. More generally, resistance can potentially spread to other types of bacteria, including human pathogens, through gene transfer mechanisms special to bacteria (Dixon, 2000)…. A U.S. Center for Disease Control and Prevention (CDC) literature review indicates that certain antibiotic resistance genes in Salmonella-bacteria that can cause severe food poisoning in people-might have emerged following antibiotic use in Asian aquaculture (Angulo, 1999).”
(–Goldburg, R. et al. (2001). Marine aquaculture in the United States: Environmental Impacts and Policy Options. Pew Ocean Commission, p. 16-17..)

This practice is seriously harmful to wild fish. The 2002 collapse of the pink salmon run on the central B.C. coast is blamed on parasites known as sea lice, contracted from the area’s numerous salmon farms. Much of the salmon farmed in the Pacific Ocean is, in fact, Atlantic salmon — an exotic species. According to the Department of Fisheries and Oceans, Atlantic salmon have been found in over 81 BC rivers and streams. It is worth noting that only a small portion of BC rivers have been surveyed so far; meaning non-native Atlantic salmon could be inhabiting many more. Atlantic salmon have also been found in rivers in Alaska and the Pacific Northwest. These fish ultimately compete with and displace precarious native stocks.

Most importantly, it’s unhealthy to eat regularly, as the fish are fed food contaminated with dioxins, resulting in high levels of PCBs in the flesh of the fish. Environmental Defense Fund has issued a health advisory for farmed salmon due to high levels of PCBs recommending that adults only consume one to two meals of farmed salmon per month. The groundbreaking study, A Global Assessment of Organic Contaminants in Farmed vs. Wild Salmon: Geographical Differences and Health Risks was released January 2004 in the respected journal Science. The study, which is being considered the most thorough analysis of farmed and wild salmon to date, found in most cases that consuming more than one serving of farmed salmon per month could pose unacceptable cancer risks, according to United States Environmental Protection Agency (EPA) standards for determining safe fish consumption levels. Farmed salmon were found to have up to 10 times higher levels of PCBs and dioxins than wild salmon. Chemical dyes are used to make the flesh resemble the natural coloration of wild salmon – One of the dyes, canthaxanthin, has been linked to retinal problems in humans. Pesticide residues are not tested for by the FDA.

Remember, our pets are smaller than we are, and most of them consume the same food every day, for every meal, day in and day out. This is one of the main reasons we are big proponents of rotation of food for our pets. Nutritional variety and fresh whole foods are important for all of us, ensuring a broader range of nutrients and enzymes, as well as the minimization of these sorts of potential contaminants found in our food supply. If one serving per month of farmed salmon poses unacceptable cancer risk for humans, think of what it could be for a much smaller animal, every meal of every day.
If you see salmon listed on a product label, make sure to ask that company whether the fish is wild or farmed. Let them know you won’t feed this product if it contains farmed salmon. In fact, we wish that pet food companies would find more sustainable sources of fish, as many populations of wild salmon are under great pressure, and the volume needed to sustain the giant pet food demand is significant. We do carry some wild salmon products in the store, but we encourage pet food companies to consider sourcing more sustainable species of fish for their treats and foods. Most of it is a marketing challenge, as a fish like Pollock isn’t as readily recognized by the public and perhaps doesn’t sound as delicious.